Related Experiment Video
Updated: Jun 6, 2026

Construction and Characterization of External Cavity Diode Lasers for Atomic Physics
Published on: April 24, 2014
Wavelength-modulation detection of acetylene with a near-infrared external-cavity diode laser
Abstract:
An external-cavity diode laser operating at 1500 nm was used to record the combination band of acetylene (C(2)H(2)). By combination of wavelength-modulation spectroscopy with a noise-canceler detection circuit, a minimum detectable absorbance of 4.8 × 10(-4) with a 300-ms time constant was achieved, although this result was limited by étalon fringes. When combined with this detection technique, continuous, widely tunable output from an external-cavity laser is ideally suited for high-resolution absorption spectroscopy with excellent sensitivity.
Related Concept Videos
Flame Photometry: Overview
Inductively Coupled Plasma Atomic Emission Spectroscopy: Instrumentation
There are three main types of inductively coupled plasma atomic emission spectroscopy (ICP-AES) instruments: sequential, simultaneous multichannel, and Fourier transform instruments, with the latter being less commonly used.
Gas Chromatography: Types of Detectors-II
Gas Chromatography: Types of Detectors-I
TCD is the earliest and most widely used detector that operates by measuring the changes in the thermal conductivity of the carrier gas. When a sample compound enters the detector,...

